ZigBee协议部分
前段时间看到有的人卖得很贵,觉得不该如何,资料共享才是王道。
请问下,你是求资料还是发布资料???
Introduction
(This introduction is not part of IEEE Std 802.15.4-2003, IEEE Standard for Information technology—
Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific
requirements—Part 15.4: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications for
Low-Rate Wireless Personal Area Networks (LR-WPANS).)
IEEE Std 802.15.4-2003
This standard defines the protocol and interconnection of devices via radio communication in a personal
area network (PAN). The standard uses carrier sense multiple access with a collision avoidance medium
access mechanism and supports star as well as peer-to-peer topologies. The media access is contention
based; however, using the optional superframe structure, time slots can be allocated by the PAN coordinator
to devices with time critical data. Connectivity to higher performance networks is provided through a PAN
coordinator.
This standard specifies two PHYs: an 868/915 MHz direct sequence spread spectrum (DSSS) PHY and
a 2450 MHz DSSS PHY. The 2450 MHz PHY supports an over-the-air data rate of 250 kb/s, and the
868/915 MHz PHY supports over-the-air data rates of 20 kb/s and 40 kb/s. The PHY chosen depends
on local regulations and user preference.
Introduction
(This introduction is not part of IEEE Std 802.15.4-2003, IEEE Standard for Information technology—
Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific
requirements—Part 15.4: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications for
Low-Rate Wireless Personal Area Networks (LR-WPANS).)
IEEE Std 802.15.4-2003
This standard defines the protocol and interconnection of devices via radio communication in a personal
area network (PAN). The standard uses carrier sense multiple access with a collision avoidance medium
access mechanism and supports star as well as peer-to-peer topologies. The media access is contention
based; however, using the optional superframe structure, time slots can be allocated by the PAN coordinator
to devices with time critical data. Connectivity to higher performance networks is provided through a PAN
coordinator.
This standard specifies two PHYs: an 868/915 MHz direct sequence spread spectrum (DSSS) PHY and
a 2450 MHz DSSS PHY. The 2450 MHz PHY supports an over-the-air data rate of 250 kb/s, and the
868/915 MHz PHY supports over-the-air data rates of 20 kb/s and 40 kb/s. The PHY chosen depends
on local regulations and user preference.
kao
看不懂
要有中文就好了
中文部分 , 楼主的英文跟下面这差不多 , 非常简单的介绍 .
ZigBee 就是 IEEE 802.15.4,為無線裝置之間的低功率短距通訊標準。此標準歸類為無線個人區域網路 (Wireless Personal Area Network,WiPAN);該區域網路亦包含藍芽 (IEEE 802.15.3) 標準。
ZigBee 標準已逐漸引起商業與軍事產業的興趣,適用於如無線感測器網路、家庭自動化,與工業級控制的應用。ZigBee 標準之所以會逐漸受到重視,即因為 ZigBee 適用於可形成自組 (Self-forming) 與自療 (Self-healing) 的隨建即連 (Ad hoc) 網路或嚙合 (Mesh) 網路裝置。此方案的中央「PAN coordinator」裝置,將監控網路組態的情形。在最近幾年中,感測器網路亦成為軍事/戰場應用的研究主題。因此將 ZigBee 標準用於定義 Ad hoc 戰場智慧型方案的通訊作業,亦引起更多的注意。
ZigBee 規格之所以適用於遠端無線感測器的原因之一,即由於其低功率的 PHY 實體層 (Physical layer)。大致上來說,PHY 規格可讓 ZigBee 裝置以下列 3 種頻帶之一進行作業:868 MHz (歐洲)、915 MHz (北美),與 2.4 GHz (世界通用)。ZigBee 收發器最常用的即為 2.4 GHz 頻帶,並使用 OQPSK (Offset Quadrature Phase Shift Keyed) 調變串流。與類似架構相較,OQPSK 僅需較低功率亦可達到等同或較佳的傳輸率,因此成為傳統 QPSK 的衍生架構。OQPSK 使用 90 度的最大相位轉換 (Phase transition),將符碼 (Symbol) 轉為下 1 個符碼。此特性可避免符碼過衝 (Overshoot),且所需的傳輸功率略低於傳統 QPSK 調變架構。此設計整合 5 MHz 通道頻寬,可讓裝置以合理功率達到最高每秒 250 kb 傳輸率。
shenma
zigbee現在用的人多嘛?
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